The present invention relates to an inkjet printing method and apparatus and, more particularly, to an inkjet printing method and apparatus which uses centrifugal force of an ejection head and a viscosity change of ink during the rotation of the ejection head to eject a predetermined amount of the ink onto paper.
Conventional inkjet printing methods use a carriage moving method in which the ejection head reciprocates rectilinearly to discharge the ink onto paper or use a stationary operating method in which a fixed line head having a plurality of nozzles disposed in a row is used to discharge the ink onto paper from the plural nozzles. Such conventional inkjet printing methods employ various means to obtain an ink ejecting force.
For instance, in an inkjet printer using a bubble jet printing method, which is disclosed in U.S. Pat. No. 4,723,129, the ejecting force is obtained by the pressure of bubbles produced when the ink is heated. Such a printer needs an ink heating device that shortens the life of a head.
A Kyser-type inkjet printer, disclosed in U.S. Pat. No. 3,683,212 uses the deformation force of a piezoelectric element, which is created when a voltage is applied, as the ejecting force. In this printer, a stack of costly piezoelectric elements should be provided.
An inkjet printer disclosed in Japanese Laid-open Patent publication sho 55-11763 uses ink having variable electrical viscosity. This printer requires an additional compressor for producing the ejecting force.
As indicated above, in order to obtain the ejecting force of the ink, the conventional printers need an additional device, such as a heating device, piezoelectric element or compressor. Especially, the carriage mode printer needs a mechanical component such as a belt pulley for converting the rotation movement of a motor into rectilinear movement because the head must reciprocate rectilinearly. In the stationary line head, since the head must be larger than the width of a sheet of paper, the printer using a line head exhibits reduced reliability and is expensive.